With the declining availability of energy sources and increasing concern for environmental contamination by municipal solid waste (MSW) and sewage-treatment sludges, a number of proposals have been made which will, on the one hand be capable of converting MSW to useful energy and, on the other hand, destroying or eliminating the sludge disposal problem.
It has long been recognized, in addition, that the only long-term economically available energy source currently exploitable in the United States is coal which can be utilized with great effectiveness upon gasification.
It should also be noted that incineration of sludge and MSW produces atmospheric pollutants and hence this technique is not a solution to environmental problems.
In practice it has been found that coal gasification, being an endothermic process, is frequently uneconomical and that conventional techniques for the gasification of MSW and sludge, likewise are unsatisfactory.